feat(audit): Apply TreatWarningsAsErrors=true to 160+ production csproj files

Sprint: SPRINT_20251229_049_BE_csproj_audit_maint_tests
Tasks: AUDIT-0001 through AUDIT-0147 APPLY tasks (approved decisions 1-9)

Changes:
- Set TreatWarningsAsErrors=true for all production .NET projects
- Fixed nullable warnings in Scanner.EntryTrace, Scanner.Evidence,
  Scheduler.Worker, Concelier connectors, and other modules
- Injected TimeProvider/IGuidProvider for deterministic time/ID generation
- Added path traversal validation in AirGap.Bundle
- Fixed NULL handling in various cursor classes
- Third-party GostCryptography retains TreatWarningsAsErrors=false (preserves original)
- Test projects excluded per user decision (rejected decision 10)

Note: All 17 ACSC connector tests pass after snapshot fixture sync

src/EvidenceLocker/StellaOps.EvidenceLocker/Api/VerdictEndpoints.cs

@@ -20,8 +20,7 @@ public static class VerdictEndpoints
     public static void MapVerdictEndpoints(this WebApplication app)
     {
         var group = app.MapGroup("/api/v1/verdicts")
-            .WithTags("Verdicts")
-            .WithOpenApi();
+            .WithTags("Verdicts");
 
         // POST /api/v1/verdicts
         group.MapPost("/", StoreVerdictAsync)